Roofs - michigan.gov · STEEL JOISTS Costs of solid rolled or open-web joists, per square foot of roof area, including connections, ties, and braces. Depth is for open-web joists.
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EXPLANATION
The general headings for roof structures in the Segregated Cost sec-tions include the complete roof structure: rafters, purlins, sheathingor deck, bracing and ties. If a more detailed cost is needed, use thetables in this section.
WOOD RAFTERS
Cost per square foot includes necessary ties, ridges and bracing.Ceiling joists should be added. For pitched roofs, use the multipli-ers in the Roof Slope table. For prefabricated trussed rafters, seePage 3, in this section.
For roof components of sloping roofs, multiply by the figures givenbelow to obtain the cost per square foot of horizontal projection.
RISE MULTIPLIER RISE MULTIPLIER 1½ to 12 1.01 6 to 12 1.12 2 to 12 1.01 8 to 12 1.20 3 to 12 1.03 12 to 12 1.42 4 to 12 1.06 15 to 12 1.60 5 to 12 1.08 18 to 12 1.80
These multipliers may also be used to convert the horizontal pro-jected area to the actual roof area for sloping roofs.
WOOD CEILING JOISTS
DIMENSIONS SPACING (inches) 12" o.c. 16" o.c. 20" o.c. 24" o.c. 2 x 4 $1.33 $1.04 $ .85 $ .722 x 6 1.59 1.23 1.03 .862 x 8 1.86 1.46 1.28 1.112 x 10 2.35 1.84 1.51 1.282 x 12 2.77 2.15 1.78 1.51
TYPICAL ROOFS
EXPOSED WOOD BEAMSCosts per linear foot including sanding and finish. For rough sawnornamental beams, add 40%. Simulated plastic beams cost $5.50to $6.50 per linear foot.
SIZE COST SIZE COST SIZE COST 2 x 6 $2.95 4 x 8 $ 7.60 6 x 12 $20.55 3 x 6 5.50 4 x 12 10.65 6 x 14 23.00 3 x 8 6.55 6 x 8 13.15 8 x 12 28.05 4 x 6 6.25 6 x 10 16.60 8 x 14 30.95
STEEL JOISTSCosts of solid rolled or open-web joists, per square foot of roof area,including connections, ties, and braces. Depth is for open-web joists.
DEPTH SPAN LIGHT MEDIUM HEAVY
8" 10' to 14' $ .85 $1.27 -----
10" 14' to 16' .88 1.44 $2.04
10" 18' to 20' 1.41 2.30 3.24
12" 16' to 20' 1.12 1.75 2.36
12" 20' to 22' 1.58 2.41 3.30
14" 18' to 22' 1.38 1.98 2.64
14" 22' to 26' 1.77 2.54 3.37
16" 20' to 24' 1.42 2.05 2.76
16" 24' to 28' 1.72 2.43 3.23
16" 28' to 32' 2.20 3.18 4.21
18" 22' to 26' 1.58 2.31 3.09
18" 26' to 30' 1.88 2.72 3.60
18" 30' to 34' 2.39 3.47 4.61
20" 24' to 28' 1.78 2.59 3.42
20" 28' to 32' 2.05 2.99 3.99
20" 32' to 36' 2.60 3.75 4.96
24" 28' to 34' 2.11 3.08 4.12
24" 34' to 40' 2.43 3.52 4.68
24" 40' to 46' 2.96 4.27 5.68
28" 40' to 48' 2.26 3.99 5.20
28" 48' to 54' 2.88 5.06 6.63
32" 50' to 56' 2.64 4.41 5.88
32" 56' to 62' 3.24 5.39 7.22
36" 58' to 64' 2.88 4.82 6.43
36" 64' to 70' 3.24 5.76 7.67
40" 66' to 72' 3.11 5.20 7.13
40" 72' to 78' 3.62 6.00 8.25
48" 82' to 88' 3.55 5.97 8.18
48" 88' to 94' 3.99 6.59 9.06
WOOD-TRUSSED JOISTSCosts of light wood flange with solid plywood web or open tubularsteel web joists, per linear foot, including ancillary connections.
TYPE SPAN LIGHT MEDIUM HEAVYPlywood . . . . . . . . . 15' to 30' $4.35 $5.20 $6.50Tubular steel . . . . . 40' to 70' 4.05 4.95 6.60
PURLINSCosts per linear foot of purlin including connections or hangers.Light Z or C flanges for pre-engineered metal buildings may run30% to 50% of the structural channel costs. Light wood nailingstrips for wood pole frame buildings may run 65% to 85% of thepurlin costs.
4" $13.95 4" $16.45 1 x 6 $1.05 -----6" 18.65 6" 21.80 2 x 4 1.35 $3.408" 23.40 8" 27.20 2 x 6 1.60 3.80
10" 28.05 10" 32.50 2 x 8 1.95 4.35 12" 32.80 12" 38.10 2 x 10 2.30 5.05 15" 39.85 15" 46.00 2 x 12 2.95 5.70
STEEL SPACE FRAMESThe following square foot costs are averages of typical three-dimen-sional roof structures for buildings requiring long two-way spans.They do not apply to architectural embellishments or patented sys-tems primarily designed for appearance and skylight areas. Costsinclude sheathing.
DOMESTypical range of costs of dome structures where the dome formsboth roof and walls. Cost per square foot of horizontal area which iscovered, for dome structure only, excluding floor, finish, lighting, etc.
Domes may also be estimated by adding up the unit costs of thecomponent parts and multiplying by an area calculated by resolvingthe dome into a rectangular structure as shown in the illustration.
30' x 30' = 900 sq. ft.4 x 30' x 15' = +1,800 sq. ft.
STEEL ROOF TRUSSESTapered steel girders will cost from 15% to 30% less for short spansto 25% to 35% less for long spans (over 80'). Costs include endconnections.
Costs are for timber or glulam industrial trusses, including end con-nections. For finished commercial trusses add 20% to 25%. Glued,laminated wood girders will cost approximately 25% to 50% lessthan bowstring trusses for short spans (up to 25'), 20% more formid-range spans (up to 45'), to 50% to 75% more for long-span gird-ers (up to 75'). Glued, laminated arches with ties, will cost approxi-mately 15% to 20% less than bowstring trusses for short spans to10% more for long spans (over 80'). Cost ranges are for trussesbearing roof loads only, not for those carrying hoists or cranes.
BOWSTRING SPAN COST – EACH TRUSS LIGHT MEDIUM HEAVY
WOOD-TRUSSED RAFTERSCosts are for prefabricated roof trusses common to light wood framing(12" to 48" on center) using 2" x 4" and 2" x 6" (up to 45' span) and 2"x 8", 2" x 10" and 2" x 12" (over 45' span) members, attached withsteel plates or plywood gussets, including ancillary items and ties.For pole-frame construction (8' to 14' spacing) with members 2" x 8"and larger with spans below 50', add 20%. Add 10% for site-builttrusses. For double trusses, count both and deduct 5% from the total.
ROOF COVERCost per square foot of roof area, including typical flashing, valleysand underlayment as required by the roofing type. Extremely steepor cut-up roofs may be 20% above the high end of the range. Forvertical or mansard applications, add 20%. Curved metal panels,add $ .60 to $2.00.
Aluminum, sheet, corrugated, crimped or tile panelspreformed, light (.0175" to .024" thick) . . . . . $1.50 – $2.90
heavy (.032" to .050" thick) including prefab lock and seam . . . . . . . . . 2.75 – 4.25
VENTILATORSCost for each range includes galvanized steel (lowest), aluminum,and stainless steel or copper (highest). For light residential installa-tions, deduct 50%.
FALSE-MANSARD FASCIAFalse-mansard framework is not normally a part of the roof struc-ture. It can be priced on a cost per square foot of vertical projection,exclusive of sheathing and cover which can be added from Page 4.
For finished soffit, add $3.20 to $5.05 for plaster or stucco, $2.00 to$4.55 for wood or $2.90 (residential) to $5.25 for metal or vinyl, persquare foot of soffit area.
FASCIA BOARDCost per linear foot for wood, metal or vinyl fascia boards. For res-idential construction, use low end of range. For 1" wood materialreduce costs by 50%.
COST RANGE COST RANGE 6" and less . . . $1.95 – $2.65 8" and over . . . $2.15 – $3.85
STEEPLESCosts are given per linear foot of height except where noted.
CUPOLASTYPE SMALL MEDIUM LARGE
(up to 10') (over 20') COST RANGE COST RANGE COST RANGE
Costs per square foot of floor area for permanent single-layer fabricstructures completely installed. For interior thermal liners, add $2.50to $5.05 per square foot.
Costs of exterior construction of dormer windows and necessarydormer structure vary greatly with the size of the dormer. It may beapproximated by applying 1/3 to 2/3 of the dwelling square foot costto the horizontal area of the dormer at the dormer eave line.
MONITOR AND SAWTOOTH ROOFS
Costs of monitor and sawtooth roofs may be built up as with any otherroof structure, adding for trusses if they exist, and then pricing the ver-tical window sections as follows: